Having being a `screen` user for over two decades, migrating to tmux has been a pain. A week ago, however I discovered a wrapper called `byobu` (1) which really helps, and controls both screen and tmux depending on which one you have on your system. It basically wraps Function keys and more to tmux, but has plenty of other features. Time will tell if it was worth installing, but I do believe it's simpler for me to use it as a transition from screen.
I've been a screen user for decades as well, and don't feel compelled to use tmux (and also tmux has one too many concepts for me, I don't need sessions). Did you find some compelling reason to switch?
byobu certainly looks good, and I'd recommend it to any new user.
Having spent a while to learn all the shortcuts of tmux and customizing my env with tpm plugins, there's low value in me re-learning a new set of shortcuts.
I also wonder how byobu users can use their system-defined Function keys while using byobu, since it seems to have set shortcuts on all these keys.
(1) https://byobu.org